Do you regularly work with cash buyers on off market deals?

Attend local meetups regularly.

Do our regular rent increase and then add on an extra $100 or $200 because you have to chase the rent Let the tenant know now that their rent will increase significantly if you have to chase them for the rent every month. 

Backstory:We rent the ADU out regularly via STR or MTR and live in the main house currently and are looking to size up.

This is especially true the finer the market is.I see a lot of different strategies from serial investors I work with regularly, and would be happy to learn more about your finer details as such.

Houston isn't making 4 unit buildings regularly.

Also, Z Wave and Zigbee radios are in sleep mode 99% of the time whereas WiFi radios are communicating pretty regularly.

They are not as scary as some make them out to be, you just want to be certain that you can regularly contribute to the principal of the HELOC/home equity loan (on top of your monthly interest only payments), so you can pay the balance off within a reasonable amount of time. 

But if you are using seller financing and a regular CRE loan, the seller will need to be comfortable subordinating.

Most investors I work with do either a regular refi DSCR loan or, take up to 75% or 80% of equity out of the home through a cash-out refi.